As ERβ has been reported to act as a tumor suppressor in various malignancies including breast, prostate, colorectal, ovarian and glioblastoma [50], further research to corroborate this function and define the mechanism of action will be essential in order to determine the value of the receptor as biomarker and therapeutic target and its utility in new approaches to combat the resistant and metastatic states of these diseases. The gene discussed is ESR2; the disease is glioblastoma.